


Let's Just Use Each Other

by StripesnBooks



Category: Undertale (Video Game)
Genre: Biting, Cunnilingus, Ecto-Penis (Undertale), Ecto-Tongue (Undertale), F/M, One Shot, Penis In Vagina Sex, Praise Kink, Sex, Smut, Vaginal Fingering, reader is female
Language: English
Status: Completed
Published: 2018-06-27
Updated: 2018-06-27
Packaged: 2019-05-29 08:33:08
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 1,494
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/15069278
Author URL: https://archiveofourown.org/users/StripesnBooks/pseuds/StripesnBooks
Summary: You felt like shit. So you find someone that makes you not feel like shit for the night.And Sans promises you a good time.Underfell Sans smut one-shot





	Let's Just Use Each Other

You never did this. You never did this, and it was obvious from the sloppy way you followed him back to his apartment and kissed each other against the closed bedroom door.

 

“you don’t do this much do ya sweetheart?” the squat skeleton pinning you to the door chuckled. You had gone to some bar you hadn’t tried yet, not willing to risk running into anyone you knew tonight, and it turned out to be a monster bar. And after buying you a few drinks and chatting you up, you had gone back to his apartment. This apartment. “heh, we need a safeword?”

 

“Pumpernickel,” you threw out on a whim, pulling him back to you to kiss him again. While his face certainly looked like bone, it didn’t feel precisely hard, and had some give. He was an excellent kisser, and his glowing red tongue sliding into your mouth was not at all unwelcome.

 

“got it, doll. hey, you got a name?” he was already shedding his jacket.

 

“No. we’re just using each other, so lets just fucking use each other tonight.”

 

“heh heh. alright sweetheart. whatever you say.” He moved to remove his wifebeater, but you stopped him.

 

One hand keeping him from pulling his shirt up, you run the other one over his face. He practically melts into your touch. “No, let me. Let me treat you tonight.” His brow bones raise. He is obviously not used to that. “Once we get in bed you can take the lead back if you want, but let me do this.”

 

He lets you.

 

You bring your other hand to cup the other side of his face, and plant a soft kiss on his forehead, leaving him shivering in anticipation. “Tell me I’m beautiful.”

 

“stars, you’re beautiful, doll.”

 

You run your hands down his face, and further along the vertebrae of his neck. “Tell me you want my body.” You place a kiss against his spine.

 

“i wanna do all kinds of things to your soft little body,” he breathes, lost in your touches.

 

You move to kiss his mouth again, this time keeping your mouth closed against his, resisting his attempts to deepen it. “Tell me you like how I taste.” You begin to finally lift his shirt up, and he lifts his arms to aid its ascent before it falls to the floor.

 

“i love how you taste, doll. can’t wait to sample more,” he growls deeply, with a wolfish grin. His hands run up and down your sides, and you let him remove your top. You even allow him to fondle your chest before carefully removing his hands.

 

You run your fingers over his bare ribs, and he lets out a needy moan. He’s panting now, and you can see something glowing in his pants. If it was any other night, you’d be far too curious to continue this. But instead you hook your fingers on the edges of his basketball shorts. “Tell me to take your pants off.”

 

“take my fucking shorts off already,” he growls again, but it definitely sounds more pleased than frustrated.

 

You follow the pants down, ending up kneeling before his erection. It’s a glowing dick, definitely shaped similarly enough to human ones you’ve seen before, but with more girth than you’re used to. It doesn’t matter tonight. He told you that you were beautiful, and that he wants your body. That’s all you need. You lick up the shaft, from head to base, where it sort of just disappears near his bone, and he bucks his hips in an effort to find relief. “Tell me you’re going to break me.” You stand back up.

 

“doll, I’ll break you as many times as you want.” You pulled your faces together, this time letting the kiss get heated. Your lips moved passionately against his teeth, and you sucked on his tongue. He retracted it to nip gently at your lips and tongue. His hands moved over your back. One traveled up, tangling in your hair, pressing your face close. The other moved down, grabbing at your ass and shoving your pants off of your hips.

 

You separate your faces just long enough for one sentence. “Now take it.”

 

He takes it.

 

He all but rips your remaining articles of clothing off, grabbing needily at your hips. He moves his face to your chest and you let your head loll back as he licks at your breasts, razor sharp teeth nipping dangerously at your nipples. His tongue feels warm and wet and electric and you want it everywhere, it was amazing in your mouth, it felt amazing on your chest, and stars, you wanted it between your legs, but you told him he could take control from this point on, so you let him.

 

It was fine.

 

You were beautiful.

He liked your body.

He was going to, with your permission, break you.

 

He dumped you on the bed, pinning your wrists and leaving warm licks all over your exposed flesh. He breathed on your neck, “remember that safeword sweetheart?”

 

“Pumpernickel.”

 

“don’t be afraid ta use it.” and he bit your shoulder. It was gentle at first, then you knew it would bruise, and then you felt it break skin. You moaned at the pleasurable pain, and he paused to lap at the dots of blood. “good girl,” he purred.

 

“Not bad yourself, hot stuff,” you panted back.

 

He chuckled darkly, and one hand moved down to your core, phalanges tracing your labia. You were already soaked, and your breath hitched as he gently pumped a couple of phalanges into you. “I can never get over how soft y’all are... how easy your body gives...”

 

he kisses you again, deep and long, and with his tongue pushing into your mouth his fingers pick up the pace, moving faster. He hooks them gently to hit your g-spot, and you moan into his mouth. For a second you think you hear him purr, but its over as soon as it starts. Your faces separate and he licks his teeth, but his fingers don’t stop. “good girl...” he licks again where the blood on your shoulder was starting to slow, not letting it congeal. He laps at the wound for a few seconds, then his fingers slow as his head dips down to you hips. He drags his tongue over your clit, and, fuck, that tingle of energy almost has you cumming immediately. But then he turns his head to the side and digs his teeth into your thigh. You hiss in pain and he laps at this wound now, before shoving his phalanges roughly back into you and finger fucking you with abandon. You cum so fast that you’re not sure if he even realized, but he must have since he starts praising you again.

 

“aaaah, yeah, cum for me human...” he licks your clit again, and the overstimulated nub burns with pleasure as he keeps it up, running the tip of his tongue around it until you come a second time, only then backing off as you lay, panting and exhausted on the bed. “hmm...” he muses, tapping one of his fingers, coated in your juices, to his mandible. “not quite broken yet. how man ya think you can take?”

 

“m-more... than you can... give...” you pant out challengingly.

 

“really now? Let’s see ‘bout that.”

 

He lines up and begins to push his glowing red dick into you, and fuck, it’s so much more than just his fingers, but damn it fills you up so good, and your body eagerly stretches to accommodate it. he sinks in slowly the first time until he hilts, both of you panting and breathless now. He looks down at your face in pleasure and... awe? No, no it can’t be, you’re just using each other. And then he leans down and bites your wounded shoulder again, but so much deeper this time, and you scream, and almost at the same time he pulls his hips back and begins to pound into you with so much force that the bed is creaking and you’re whimpering, and shit he’s biting down harder, but you don’t use the safe word, you simply lose yourself in the bliss of pleasure and pain. You cum for a third time, sooner than you expected, and his rhythm stutters as his hot load spills into you, and your body greedily milks him for all he has.

 

He slows, and pulls away to look at you with a bloody and satisfied grin. Your eyes are closed, blissed out and somewhat in fear of what your shoulder and thigh look like.

 

“hey. doll. look at me,” he pats your cheek lightly. “ya good?”

 

You weakly open your eyes and shudder a bit at the sight of your blood on his bones. “... yeah. ‘m good.”

 

“good.” His eyes seem to flash and his smile turns predatory. “’cuz I don’t think yer broken just yet.”

**Author's Note:**

> Found this while I was looking through my files; thought some of you fellow sinners might enjoy it. 
> 
> if you liked it, consider buying me a ko-fi  
> https://ko-fi.com/stripesnbooks


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